Tool box carriers are well known in the art. They usually consist of a larger tool chest provided with four pivotable casters allowing the tool box and the tool chest to be carried onto level surfaces.
These conventional tool carriers suffer from major drawbacks: it is not easily possible to climb or to descend stairs with these carriers and it is not easily possible to raise or to lower the tool box with respect to the tool carrier to bring the tool box to a position where the contents of the tool box may be browsed by the user.
U.S. Pat. No. 4,249,749, issued on Feb. 10, 1981 to Leroy Collier and entitled "Mobile Lift Cart" discloses a tool box carrier free of the above drawbacks of the conventional tool chests used as tool box carriers. The tool box carrier of Collier includes a wheeled base so configured as to allow stairs to be climbed and descended. Furthermore, Collier's tool box carrier includes a tool box support mounted to the wheeled base via a scissor type mechanism allowing the tool box support to be raised or lowered with respect to the wheeled base.
While the tool box carrier disclosed by Collier is a major improvement over the conventional tool chests used as tool box carriers, it has nevertheless major drawbacks. Firstly, when the tool box support is to be raised from the wheeled base, the user must manually pull the support upwardly, which can be difficult and even dangerous when the tool box contains heavy tools. Secondly, the tool box has to be fixedly mounted to the tool box carrier since the tool box is tilted when stairs are ascended or descended. Thirdly, the tools present in the tool box during stairs ascension or descent are likely to be damaged because of the tilt imposed on the tool box.